Pneumatic-kinetic drilling system

ABSTRACT

A drilling system is disclosed which relies on the weight and reciprocating movement of the drill column to provide actuation and rotation of the drill bit at the bottom of the bore hole. A pneumatic power source located immediately above the bit is driven by raising the suspended drill column by means of draw works and releasing the column to convert the kinematic motion of the column into fluid power in the pneumatic power source. The compressed fluid enters a pneumatic chamber and causes rotation of the drill bit as it engages the sides and bottom of the bore hole. The system may also include a source of drilling fluid pumped from the surface through the drill column and pneumatic power source to the bottom of the well bore to return the cuttings to the surface. The pneumatic fluid after it drives the bit and is expanded may be mixed with the drilling fluid to provide a lift assist to the fluid as it is returned to the surface with the drill cuttings.

United States atent [1 1 Van Huisen [451 Aug. 12, 1975 PNEUMATIC-KINETICDRILLING SYSTEM [22] Filed: Jan. 3, 1974 [21] Appl. No.: 430,643

[76] Inventor:

[52] US. Cl. 175/97; 175/69; 175/103; 175/106; 175/107; 175/170 [51]Int. Cl. E21B 3/12; E21B 5/00 [58] Field of Search 175/93, 106, 107, 97,100, l75/101,103, 170, 319

[56] References Cited UNITED STATES PATENTS 888,164 5/1908 Hardsocg175/100 X 1747398 2/1930 Short 175/93 X 1,965.56 7/1934 Bannister...175/103 2,635 852 4/1953 Snyder 175/93 1802.640 8/1957 Boucher et a1.175/93 X 3047.079 7/1962 Wepsala 175/107 3,807,512 4/1974 Pogonowski eta1. 175/106 FOREIGN PATENTS OR APPLICATIONS 735 8]8 4/1943 Germany175/93 Primary E.raminerDavid H. Brown Attorney, Agent, or Firm-MarvinE. Jacobs 5 7 1 ABSTRACT A drilling system is disclosed which relies onthe weight and reciprocating movement of the drill column to provideactuation and rotation of the drill bit at the bottom of the bore hole.A pneumatic power source located immediately above the bit is driven byraising the suspended drill column by means of draw works and releasingthe column to convert the kinematic motion of the column into fluidpower in the pneumatic power source. The compressed fluid enters apneumatic chamber and causes rotation of the drill bit as it engages thesides and bottom of the bore hole. The system may also include a sourceof drilling fluid pumped from the surface through the drill column andpneumatic power source to the bottom of the well bore to return thecuttings to the surface. The pneumatic fluid after it drives the bit andis expanded may be mixed with the drilling fluid to provide a liftassist to the fluid as it is returned to the surface with the drillcuttings.

19 Claims, 13 Drawing Figures PATENTEU AUG 1 2 I975 SHEET all! p I!!!lllrll lv- M KmJ PNEUMATIC-KINETIC DRILLING SYSTEM BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates to anew and improved drilling system and, more particularly, to apneumatickinematic system utilizing the weight of the suspended drillcolumn as a source of power for operation of a down-hole pneumatic unitfor cutting and drilling action of a rotating drill bit. The inventionwas disclosed in Disclosure Document No. 013208 filed in the US. Pat.Office on Sept. 5, 1972.

2. Description of the Prior Art The conventional method of drilling abore hole into the earths crust commences with site preparation afterentry and water supply is realized. Site preparation usually includesconstruction of a concrete cellar over which a derrick and otherancillary drilling equipment is installed. At the derrick floor locatedabove the concrete cellar, a rotary table is installed which rotatesduring the drilling process. A drilling bit is attached to a sub-collarwhich links it with the drill stem. The subcollar with the bit securedto it is suspended just below the rotary table and a drill collar isinserted and screwed tight to the bit and sub-collar with power tongs.

More lengths of heavy metal drill collar are added as required toprovide sufficient weight followed by hollow drill stem in enoughlengths to make up the proper length of drill string. The drill collaris subsequently attached to a square section of pipe known as a Kellywhich fits into a square opening prepared through the rotary table. Whenpower is applied to rotate the rotary table, the Kelly in the attacheddrill pipe and drilling bit simultaneously rotate pressing against thebore bottom to effect drilling.

The section of the Kelly extending above the rotary table is fastened toa swivel head which is held by a cable attached to a draw workspermitting the lifting or lowering of the entire drill column by thedraw works operator. During drilling a drilling mud, gas or fluid ispumped through hoses attached to the swivel head and passes into andthrough the drill column to cool the drill bit and return drill cuttingsto the surface. In the annular space between the drill pipe and wellcasing, this mud additionally lubricates the drill bit, keeps the borecool and stabilizes the walls of the bore. Especially in the case wherethe bore hole passes through porous or fissured ground, the drilling mudexudes into the openings until the larger particles deposit therein toform a thin, hard filter cake.

A drilling assembly of this type requires a separate source of power forpumping the circulating drilling mud, for the draw works which winds andunwinds the cable to control the tension and regulate the-weight throughthe drill string on the drilling bit and for rotating the turn table.Power is also required for lighting, pumping water and other auxiliarypower needs. Several diesel engines which consume large amounts ofdiesel fuel are utilized to supply the energy requirements of thedrilling rig. The size and height of the rig coupled with the amount ofavailable power are principle factors which limit the depth to whichdrilling rigs can bore and the diameter of the bore hole. Other limitingfactors are the weight of the drill column, the rotation of the drillcolumn and the ability to pump the circulating fluid through the drillcolumn to the bottom of the bore hole and back to the surface throughthe annulus. The deeper a bore hole is drilled, the more power isrequired to accomplish drilling. The deepest bore hole depth limitationsare related to the tremendous weight of the lengthening drill pipecolumn which must be constructed of the strongest heavy gauge steel tosustain the tremendous torque and prevent twistoffs. Furthermore, atremendous amount of power is required to pump drilling mud from greatdepths to the surface.

Moreover, as the depth of the bore hole increases, rotation of the drillcolumn may cause a whipping of a portion of the rotating column againstthe side wall of the bore hole. The loss of metal from abrasion andgrinding will weaken the drill pipe and make it more susceptible totwist-off by the torque forces being subjected to the long drill column.

As wells are drilled deeper and costs continue to rise, it becomesnecessary to minimize damage to the hole and to the protective casing.It would be further desirable to minimize drill-pipe torque and thetensile strength requirements, quality and costs of the drill pipe. Oneapproach satisfying many of these requirements has been provided by avariety of down-hole motors such as mud-drive turbines, positivedisplacement motors and electrically powered motors. The most promisingof these types of motors has been the turbines and positive displacementmud motors, since mud is already used to remove cuttings from the wellbore in most drilling operations. These systems have not found extendeduse since they are mainly useful in straight-hole drilling due toeconomic problems caused by bearings and fast wearing of bits.Horsepower input has been limiting and the penetration rate and durationof tool life have not been satisfactory. The down-hole motors have founduse mainly in the drilling through diamond drillable soft formationssuch as shales, dolomites, some limestones and some sandstones. Anotherlimiting factor is the mud-handling system since down-hole motorsconvert hydraulic horsepower to mechanical horsepower, the motor must besupplied with sufficient mud at a high enough rate to fit its specificrequirements.

The environment of the hole is also important in considering the use ofa down-hole motor since certain types of crudes are found to dissolve orswell the rubber coated portions of the down-hole motor system and atemperature of 300F is normally the limit for application of down-holemotors. Stabilization of the tool to prevent the bit from moving onbottom and creating an out of drift hole is also a factor in the use ofthese motors.

SUMMARY OF THE INVENTION The present invention in common with thedownhole motor does not require rotation of the drill column. Thedrilling system of the invention doesnot require hydraulic horsepowerdelivered from the surface in high volume and pressure. In contrast, thedrilling system of the invention is provided with a pneumatic orhydraulic power source located immediately above the bit and connectedto the drill column. A source of air, gas or fluid such as drilling mudis delivered to the power source. The power source is operated byreciprocating the drill column by actuating and releasing the drawworks. Thus, the present invention utilizes the great weight of thesuspended drill column as a source of kinetic energy to compress gasesor fluids for utilization as a power source available at the lowerextremity of the bore hole. During operation of the down-hole pneumaticor hydraulic power chamber, the mechanical rotary output thereof isutilized to rotate the drill bit without necessitating rotation of thedrill pipe column.

Other aspects of the invention relate to ejecting air or gas from thepneumatic chamber after being used to power the rotation of the bitsinto the drilling mud. The bubbles of gas serve to assist in raising thedrilling mud through the annulus between the casing and the drill bit upto the surface. The drilling system of the invention eliminates the riskof twisting and breaking the drill bit from torque since surfacerotation of the entire drill column is obviated. Thus, the inventionpermits use of lighter weight drill pipe in deep well drilling. Thesystem of the invention further reduces the bulk weight of the rig andfuel consumption by utilizing the kinetic power potential of the heavydrill column. The system of the invention further permits drilling ofdeeper wells into the earths crust than has been possible or practicalbefore by permitting the use of light-weight drill pipe and providing adrilling mud lift assist by the injection of the exhaust compressed gasor fluid into the circulating drillingfluid. Another feature of theinvention relates to formation of spiral grooves on the drill columnwhich creates a swirling effect to prevent buildup of filter cake on thecasing. This is necessary in the system of the invention since the pipestem does not rotate to provide the desired swirling flow of the mud tothe surface.

These and many other attendant advantages of the invention will becomeapparent as the invention becomes better understood by reference to thefollowing detailed description when considered in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic and plan view ofa first embodiment of a drilling system;

FIG. 2A is a front sectional view of the first embodiment showing thepiston in lowered position;

FIG. 2B is a front sectional and plan view showing the piston in raisedposition;

FIG. 3 is a cross-sectional view taken along line 33 of FIG. 2B; I

FIG. 4 is a schematic view of a further embodiment;

FIG. 5A is an enlarged front view partly in section of the embodiment ofFIG. 4 with the piston shown in raised position;

FIG. 53 illustrates the piston in lowered position and the expanders inextended position;

FIGL 6 is a cross-sectional view taken along line 66 of F IG. 5B;

FIG. 7 is a sectional view of an intermediate gas lift compressionchamber;

FIG. 8 is a sectional view taken along line 88 of FIG. 7;

FIG. 9 is a front plan view of a multiple compressor embodiment;

FIG. 10 is a sectional and plan view of a further embodiment of amultiple compressor embodiment; and

FIG. 11 is a cross-sectional view taken along line 11-11 of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. l-3, thedrilling system of the invention generally comprises a rotatable cuttingbit 10 connected to fluidic rotary power source 12 which is in turndriven by a reciprocating pressure intensifier 14. The bit 10, powersource 12 and intensifier 14 all form a down-hole motor unit 44 locatedat the lower end of the light-weight drill pipe 16. Reciprocating actionis provided by a cable 18 connected to'the intensifier l4 and to thedraw ,works 20 located on the surface. Reciprocation is suitablyeffected by cyclic actuation of the power unit22' by means of controller24 to provide a cyclic lifting force and downward'release action on thecable 18. and appended structure.

The surface also contains conventional drilling structure andaccessories such as a foundation or platform 26 over which isconstructed a derrick 28, the top of which contains a crown pulley block30 receiving the cable 18. I

The systemof the invention also includes a source of fluid .for deliveryto the pressure intensifier 14. The fluidmay be gaseous or liquidfAsshown in FIG. 1, drilling mud conventionally used to remove the cuttingsfrom the bottom 32 of the bore hole 34 may be utilized as the hydraulicfluid. The mud supply emanates from a mud supply 36 and is pumped bymeans of mud pump 38 which delivers a supply of drilling mud underpressure to the interior40 of the drill stem 16 through the grippinghead 42. 1

Referring now to FIG- 2A, the mud flows through the interior of drillstem. 16 and as it reaches the combined down-hole drilling unit 44 itflows into a bypass line.46 which encircles the unit 44 and has an exitorifice 48 which applies a highpressure stream of mud onto the rotatingcutting bits 10. The mud picks up the cuttings and rises through theannulus 50, optionally assisted by .draw pumps (not shown) and isrecovered through outlet 52 where it is delivered to a mud pit (notshown) in which the cuttings are removed and the mud recycled to the mudsupply 36.

The down-hole drilling-unit 44 contains a reciprocating piston 52 havinga piston rod 54 attached to cable 18. The piston reciprocates within apiston chamber 56 formed by the outerwal1s58 of the unit 44. Port valves60 are formed in the upper terminus of the chamber 56 which are closedduring the uppermost travel of the piston 52. As the piston 52 fallswhen the tension on cable 18 is released, mud from annulus 50 will enterthe port valve 60and'fill the chamber 56 above the top of the piston 52.Simultaneously as the piston falls it will force the mud containedwithin the chamber 56 below the piston head 52 out under high pressurethrough angularly directed exit ports 62. This high pressure 'mud willbe directed against the vanes 63 of turbine rotor 64, the shaft 65 ofwhich is rotatably mounted within a bearing 72 mounted in the lower wallof the piston chamber. The rotor 64 is in turn connected to a spindlegear 76 which rotates gears 78, 80 and 82 to transmit power to shaft 84mounted within bearings 86 and 88. The shaft 84 is in turn connected tothe rotatable cutting bit 10. The mud continues past the rotors, aroundthe gears to lubricate and cool the gears, and through ports 90 and 92within bearing plates 94 and 96 and passes out through the apertures 98within the casing of unit 44 to provide high pressure mud assisting thelift of the drilling mud to the mud pit through the annulus 50.

As shown in FIG. 28, as the piston 52 rises by retensioning the drawworks, mud passes through unidirectional check valves 100 and fills thechamber 56 as the piston simultaneously forces mud out through the portvalves 60 into the annular mud column.

The rotation of the turbine rotor 64 and bit may develop a torque in thedrill pipe 16. The bit can be sta bilized and the torque minimized byattaching a plurality of centralizing spacers 110 which engage the wall35 of bore hole 34 or casing 97 if the hole is cased. Usually threecentralizers are sufficient in order to maximize the open annularpassage for removing the drilling fluid. The torque could also becounteracted by attaching a kelly to the top of the drill pipe columnand slowly rotating the column in a direction opposite to that of thedeveloped torque.

The slow rotation of the drill column will also assist in the lift ofthe drilling fluid by inducing a swirling motion to the fluid. Thisswirling motion is further enhanced by applying a spiral band on thedrill column, suitably by attaching a plurality of flanges 112 to thedrill pipe segments. The flanges are preferably angled upwardly and thedirection of the spiral should work in cooperation with rotation of thedrill pipe column.

The illustrated reciprocating kinematic-hydraulic drilling systemincorporates only one direct reciprocating movement and a resultingrotary movement and is simple and dependable to operate. The systemutilizes the extensive weight of the suspended drill pipe column as asource of kinetic energy which is transferred to the fluid to drive therotary hydraulic power source for the bit. Since the drill pipe columnis not rotated at high speed, the risk of twisting and breaking thedrill pipe from abrasion and torque is eliminated. Also, since thedanger of twist-off from torque is eliminated, a lighter weight drillpipe may be utilized. The system of the invention reduces both rigweight and fuel consumption. Drilling to deeper depths becomes possibleat lower energy and equipment costs. The drilling systemof the inventionlocates the rotational power at the bit, increases bit speedappreciably, reduces drill pipe wear, increases rate of penetration andprovides straight hole drilling.

The lower part of the drive shaft may terminate in' a rotating bit subof conventional construction having external or internal threads forreleasibly securing a tool bit. The bit utilized may be a conventionalbit utilized in either conventional rotary drilling or in modified highdrill or turbo drill applications. The bit may include rotatable cuttingwheels which may be free wheeling or mechanically or hydraulicallypowered to increase the churn type of cutting action of the drill.

The drilling system of the invention will provide an intermittentpercussion and rotating cutting type of action. The motor size anddimensions will be selected to optimize the fluid volume and pressureattainable depending on the depth and other operating conditions. Thedrilling system of the invention will operate efficiently with all typesof drilling fluids ranging from water to very heavy drilling mudsincluding oil base muds, salt water muds, oil emulsion muds, clay basemuds and high viscosity muds. Also muds with all types of lostcirculating materials in concentrations to nine pounds per barrel can beutilized. The system can also operate with high-pressure gas or air. Theweight or viscosity of the fluid has little effect on the toolsperformance. The weight of the drilling mud does, however, have a directeffect on the maximum pressure increase. Free solids in drilling fluidsand especially sand can affect tool performance by accelerating bearingwear and wear of other motor elements. Sand content should be held to anabsolute minimum, less than 1%.

The initiation of the reciprocating hydraulic cutting action cannot beaccomplished until the initial depth of the hole is at least the lengthof the tool bit plus a length of drill column sufficient to provide thedesired weight for drilling and for operation of the hydraulic motor.The initial bore hole may be formed by conventional churn or rotarytechniques until the desired depth is achieved. The hydraulic piston andturbine section with attached bit is then lowered into the hole with thedrill column and the mud. circulation started until the drill pipecolumn and the annulus are completely filled and the hydraulic cylinderis filled with mud. The reciprocating action-isthen started with mudcirculation continued to remove the cuttings as the bit churns and cutsaway the sides and bottom of the hole.

For drills having outside diameters of 5 to about 8 inches and toollengths of about 20 to 25 feet, it is estimated that the flow rate ofhydraulic fluid, supplied to the turbine .by the reciprocating pressureintensifer, should be about 200 to 500 gallons per minute to provideabout 300 to 400 rpm bit speed having atorque ranging from about 200 to1,000 foot/pounds. The flow rate of fluid supplied to the turbine isthus dependent upon both the frequency of reciprocation and velocity ofthe piston of the pressure intensifier. The kinematichydraulic drillingsystem can also be used successfully with gas or air as the rotaryfluid. The volume of air required to operate the system is more thanthat required for drilling fluid but within the range of compressorcapacity utilized for normal rotary air drilling methods. About 4.5cubic feet per minute of air at 300 psi will provide the same work as 1gallon per minute of drilling fluid. Suitable performance will beprovided by pressures ranging between 300-400 psi. Because of thecompressibility of air, the system is more sensitive to weight and willtend to stall out as the pressure differential reaches'over about 200psi. Therefore, the tension of the column at the draw works has to beadjusted to determine the stall speed at the conditions of operation andis thereafter maintained above this level in order to provide thedesired rotary action. A lubricant may be added to the air stream suchas liquid soap, quar gum, gel or calcium stearate in order to lubricatethe moving surfaces of the piston chamber and rotary impeller.

A pneumatic drilling system is illustrated in FIGS. 4-8. As shown inFIG. 4 in addition to the structure shown on the surface, the systemfurther includes a compressor or pump 1 14 for supplying a pneumatic gassuch as dried air through central air pipe 116. The piston rod 118 issurrounded by a spring 120 and which piston rod 118 is connected to anupper portion of a sleeve 122 which surrounds the piston chamber. Thesleeve 122 is in turn connected to the drill pipe column 124 therebyenabling the lifting of the pipe column 124 by the cable and draw works20 and gripping head 42. The centralizers 126 in this embodiment arefixedly connected to the sleeve 122 and to the outer wall 128 of thepiston chamber. Thus, as the sleeve falls with the weight of the drillcolumn 124, the centralizers will expand outwardly against the wall 130of the bore hole and when the draw works raises the sleeve the piston132 will raise and retract the centralizers 126. The uppermost travel ofthe piston will cause abutment against the upper wall 134 which throughpiston rod 118 and the top wall 136 of the sleeve will form a forcetransfer member supporting the whole drilling assembly in tension. Thisis analagous to the manner in which the drill stem 16 of the embodimentof FIGS. 1-3 is intermittently lifted. The piston rod 118 may be keyedto the piston rod aperture 138 as shown in FIG. 6 suitably by formingthe rod with an angular surface such as a diamond or other polygonalcross section so as to minimize torque transfer to the drill column 124.

The air line 116 may be bypassed to the lower end of the chamber whereit selectively feeds air into chamber 142 when check valve 144 is openduring the up stroke of the piston 132. The mud is delivered through theannular portion 146 of the drill column and also is bypassed throughline 148 to a terminus 150 applying its stream of drilling fluid to therotatable cutting bit 10.

When the draw works releases the tension on the drill column 124, thesleeve 122 falls, the centralizers 126 expand and bind to the wall andthe piston 132 drops compressing the air and expelling it at highpressure and volume through the outlet valve 152 and onto the rotor todrive the drill bit as explained above. The air exhausts through outletports 154 mixes with the mud and serves to assist in the lifting of themud to the surface. As the tension is relieved, the spring 120 tends toreturn the piston rod 118 to its upper most limit while air entersthrough valves 144 and fills the piston chamber 142. The cycle is thenrepeated to provide another session of drilling.

Additional mud lifting assist is provided by including a plurality ofgas compression chambers along the drill pipe string 124. As shown inFIGS. 7 and 8, the compression chambers 150 can take the form of aslidably mounted annular member 152 disposed over a section 155 of thedrill pipe. Each annular member encloses a flanged disc 156 attached tothe outer surface of the pipe 155 which acts as a piston on reciprocalmovement of the drill pipe 155. A set of three expanders 158 attachesthe annular member 152 to the drill pipe 155.

A first set of inlet valves 160 are provided on the drill pipe 154adjacent the bottom of the piston chamber 162 and opposite a first setof outlet valves 164 provided on the outside wall 166 of the member 152.Another set of air inlet valves 168 are provided on the drill pipe 155near the top of the chamber 152 opposite a second set of air outletvalves 170.

As the drill pipe string 124 is released and falls, piston 156 will fallforcing air out through valves 164 into the annulus 172 containing acolumn of rising drilling mud aiding in lifting it to the surface. Theexpanders 158 will be forced outwardly and will engage the casing 174.As the piston 156 falls, valve 168 will fill the chamber 162 withanother charge of air. On the upward movement of the drill pipe 124,piston 156 will force this charge of air out through valves 170 whilethe chamber 162 below the piston 156 is being recharged with air throughinlet valves 160.

In another embodiment of the multiple air compressor lift assist shownin FIG. 9, the multiple compressors are formed by means of telescoping,collapsible drill pipe segments. For example, drill pipe segment 180 mayterminate in a plate piston 182 having a slightly larger diameter thanthe segment. The next segment having an upper lip 184 is slidablymounted over the piston 182. Flange stop 186 and seal plate 188 aredisposed equidistant from the piston 182. The piston 182 and seal plate188 are apertured to slidingly and sealingly receive the mud conduit 190and air pipe 192. Outlet valved orifices 194 are provided immediatelyabove stop plate 188 and an air inlet valve 196 is connected to air pipe192 within the compression chamber 198 formed between the piston 182 andthe stop plate 188.

As the tension of the drill pipe is released, the pipe will fall and aspiston 182 falls it will compress the air within the chamber 198 andforce it out through orifices 194 into the rising mud column within theannulus 200. A further compression chamber 202 is formed by pipe segment204 which slidingly rides over segment 206 when the pipe string isdropped. The air between piston 208 and plate 210 will be compressed andejected through outlet orifices 212.

A further embodiment of the invention in which the collapsible sleevecompressor is housed within the drill collar portion of the drillingsystem and in which the drilling mud supply is passed through directlyto the rotating drill bit is illustrated in FIGS. 10 and 11. As shown inthe drawings, the drill collar 300 is connected to the last segment 302of drill pipe in a manner to prevent rotation. For example, the drillpipe 302 suitably contains key members 304 which engage into slots 306provided in the upper end of the drill drill collar 300. An air line 308extends throughout the drill pipe train and is connected to the inletvalve 310 disposed on the upper surface 312 of the sleeve member 314.

The mud line 316 is slidably and sealingly mounted through the topmember 312 of the sleeve 314 and the bottom member 318 which then formsthe piston for compression chamber 320. The mud line 316 also extendsthrough the pneumatic rotating motor 322 which is rotatably mountedwithin the drill collar 300 by means of bearings 324. The mud pipe 316further extends through the cylindrical shaft 326 to which the rotatingcutting bit 328 is attached. The mud from line 316 is then forcedthrough passages 330 within the cutting bit 328 and lubricates and coolsthe rotating cutting heels 332 before injection onto the bottom of theholes to pick up the cuttings for return to the surface.

The air from the pneumatic motor 322 leaves the motor through passages334 in the cylinder member 326 and mixes with the mud as it risesthrough the annulus. The motor and compressor assembly is secured withinthe drill collar by means of locking mechanism 336 which is threadablyattached to the collar 300 suitably by threads reversed to the directionof rotation.

The sleeve member 314 forms an auxiliary or ancillary air storagechamber 337. As the drill stem 302 falls, the sleeve 314 and piston 318will fall compressing the air within chamber 320 and forcing it outthrough orifices 339 onto the blades of the pneumatic turbine rotor 322.As the sleeve falls, air is injected through line 308 through valve 310into the chamber 337. As the lift stroke of the reciprocating actionproceeds, a vacuum is created in chamber 320 drawing into the chamberair from chamber 337 through the valves 340.

The drilling penetration rate is a function of the weight on the bit atpercussive impact and the rotary speed of the bit. The speed can becontrolled by controlling the tension on the draw works and/orcontrolling the initial air pressure delivered to the compressionchamber by means of the setting on the delivery compressor on thesurface. Recommended bit weights for small bore holes range from 1,000to 8,000 lbs. per inch of bit diameter. The mud must be provided insufficient volume to cool and lubricate the parts and to remove thecuttings from the hole. Sufflcient pressure of mud must be provided atthe bit face so that the cuttings can be cleared from the rollingcutters by the fluid jets. The circulation of the drilling fluid may bepracticed in an intermittent manner until an optimum wall cake is formedto control water loss through porous strata and to prevent slaking orswelling of clays or clay shales exposed to water. The variable tensioncan be controlled by a clutch setting at the draw works. Reciprocationcould also be provided by a reversible engine, a walking beamarrangement or the disposition of a rotating cam member onto the cablesconnecting the draw works to the drill pipe train.

There are four general drilling methods capable of boring large diameterholes (over 3 feet internal diameter), ie (1) churn drilling, (2) augerdrilling, (3) core drilling, and (4) rotary drilling. Rotary drilling isthe most effective and efficient technique for this purpose. Largediameter holes are needed for emplacement of explosive charges and foremplacing large diameter down-hole heat exchangers for geothermalrecovery systems as disclosed in my prior U.S. Pat. Nos. 3,470,943,3,521,699 and 3,765,477.

The down-hole pneumatic or hydraulic motor of the invention is readilyadaptable to rotary drilling equipment and may be utilized in the sameapplications with minor modifications in the equipment, mainlyelimination of the rotary table and swivel. The big hole drill rig issimilar to ordinary rigs and includes the substructure, draw-works,prime-movers, mast and block and tackle. The draw-works input horsepowerfor a stationary rig for drilling a 48 to 66 inch diameter hole to adepth of 2,000 to 2,500 feet is from 1375 to 1625.

The drill string or in-hole components consist of the bit, drill collarincluding the down-hole motor and fluidic drive assembly and the drillpipe. The rolling cutter bit is the preferred tool for nearly allsubsurface materials.

What is claimed is:

l. A fluidic-kinetic drilling system comprising in combination:

a downhole assembly comprising:

a rotatable drilling bit; fluidic means for rotating the drilling bit; afluidic power source means responsive to kinetic reciprocation foractuating the fluidic means; suspending means extending from the surfacefor suspending the downhole assembly adjacent the bottom of a bore hole;and

means connected to the suspending means for reciprocating the fluidicpower source means.

2. A system according to claim 1 in which said downhole assembly isreceived within a drilling collar.

3. A system according to claim 1 further including fluid supply meansextending from the surface to the fluidic power source means fordelivering power fluid thereto.

4. A system according to claim 3 in which the sus pending meanscomprises a series of connected pipe sections forming a drill column andsaid fluid supply means is received within said drill column.

5. A system according to claim 4 further including means connected tothe outside surface of the drill column for inducing a swirling motionin the rising mud column.

6. A system according to claim 5 in which the swirling means includes aplurality of angled flanges connected to said drill column.

7. A system according to claim 5 in which the drill column includes aplurality of reciprocably actuated compression chambers, means fordelivering gas to said chambers and means for exhausting compressed gastherefrom into the rising mud column to assist the lift thereof.

8. A system according to claim 3 further including means for deliveringdrilling mud adjacent the bottom of the bore hole and establishing anupward swirling of drilling mud thereby providing means for assisting incirculating drilling fluid from the surface to the bottom of the borehole and back to the surface.

9. A system according to claim 8 in which said drilling fluid isutilized as the power fluid and the circulating means encircles saidpower source means.

10. A system according to claim 9 further including fluid pass-throughmeans extending through the rotating means and drilling bit forreceiving the power fluid from the power means.

1 1. A system according to claim 8 in which the power fluid is acompressible gas and said rotating means includes a pneumatic rotor.

12. A system according to claim 11 further including means for expellingthe exhaust gas from the pneumatic rotor into the rising drilling mud toassist the lift thereof.

13. A system according to claim 3 in which the fluidic power sourcemeans includes a fluid compression chamber.

14. A system according to claim 13 in which said compression chamberincludes a piston chamber and a piston.

15. A system according to claim 14 in which the chamber includes a pairof fluid inlets and outlets on each side of the piston to form adouble-acting piston chamber.

16. A system according to claim 14 in which the fluid compressionchamber includes a top member having a keyed opening and acorrespondingly key-shaped piston rod received therein to preventrotation of said chamber.

17. A system according to claim 14 in which the compression chamberincludes an outer sleeve member slidably mounted on an inner member.

18. A system according to claim 17 further including expandable membersconnected to said sleeves during relative movement thereof.

19. A system according to claim 18 in which said expandable memberscomprise at least three metal members, each connected to said inner andouter sleeves.

1. A fluidic-kinetic drilling system comprising in combination: adownhole assembly comprising: a rotatable drilling bit; fluidic meansfor rotating the drilling bit; a fluidic power source means responsiveto kinetic reciprocation for actuating the fluidic means; suspendingmeans extending from the surface for suspending the downhole assemblyadjacent the bottom of a bore hole; and means connected to thesuspending means for reciprocating the fluidic power source means.
 2. Asystem according to claim 1 in which said down-hole assembly is receivedwithin a drilling collar.
 3. A system according to claim 1 furtherincluding fluid supply means extending from the surface to the fluidicpower source means for delivering power fluid thereto.
 4. A systemaccording to claim 3 in which the suspending means comprises a series ofconnected pipe sections forming a drill column and said fluid supplymeans is received within said drill column.
 5. A system according toclaim 4 further including means connected to the outside surface of thedrill column for inducing a swirling motion in the rising mud column. 6.A system according to claim 5 in which the swirling means includes aplurality of angled flanges connected to said drill column.
 7. A systemaccording to claim 5 in which the drill column includes a plurality ofreciprocably actuated compression chambers, means for delivering gas tosaid chambers and means for exhausting compressed gas therefrom into therising mud column to assist the lift thereof.
 8. A system according toclaim 3 further including means for delivering drilling mud adjacent thebottom of the bore hole and establishing an upward swirling of drillingmud thereby providing means for assisting in circulating drilling fluidfrom the surface to the bottom of the bore hole and back to the surface.9. A system according to claim 8 in which said drilling fluid isutilized as the power fluid and the circulating means encircles saidpower source means.
 10. A system according to claim 9 further includingfluid pass-through means extending through the rotating means anddrilling bit for receiving the power fluid from the power means.
 11. Asystem according to claim 8 in which the power fluid is a compressiblegas and said rotating means includes a pneumatic rotor.
 12. A systemaccording to claim 11 further including means for expelling the exhaustgas from the pneumatic rotor into the rising drilling mud to assist thelift thereof.
 13. A system according to claim 3 in which the fluidicpower source means includes a fluid compression chamber.
 14. A systemaccording to claim 13 in which said compression chamber includes apiston chamber and a piston.
 15. A system according to claim 14 in whichthe chamber includes a pair of fluid inlets and outlets on each side ofthe piston to form a double-acting piston chamber.
 16. A systemaccording to claim 14 in which the fluid compression chamber includes atop member having a keyed opening and a correspondingly key-shapedpiston rod received therein to prevent rotation of said chamber.
 17. Asystem according to claim 14 in which the compression chamber includesan outer sleeve member slidably mounted on an inner member.
 18. A systemaccording to claim 17 further including expandable members connected tosaid sleeves during relative movement thereof.
 19. A system according toclaim 18 in which said expandable members comprise at least three metalmembers, each connected to said inner and outer sleeves.